The invention is directed to a holding device for a tool for processing a textile or non-textile sheet material for a sewing machine and a method for processing the sheet material with such a tool.
Sewing machines and embroidery machines each comprise a stitch-forming device for creating seams or embroidery patterns in a textile sheet material or sewing material. Here, the sewing material is moved or shifted step by step in a plane underneath a sewing machine head. The sewing needle is detachably connected to a needle holder arranged on the lower end of a needle bar. The needle bar projects at the bottom from the machine head and can be moved up and down by a needle bar drive in the axial direction, such that the sewing needle can perform sewing stitches. At a small distance, a presser foot bar projects parallel to the needle bar at the bottom on the machine head. As a rule, it comprises a conical or tapering, pointed lower end for coupling and mounting various presser feet. Each of the presser feet comprises a shaft corresponding to the conical end of the presser foot bar and thus can be easily placed on the presser foot bar from below. In this way, the presser foot is automatically centered and optionally brought through additional alignment means into a specified desired position. It can be fixed there, e.g., by a holding clip or other attachment element. Such presser feet are known in various embodiments—each according to the type of stitches to be performed. For sewing, the presser foot bar is lowered with the presser foot, such that the presser foot bar contacts the material to be sewn. The presser foot bar is pressed downward by the force of a spring, so that the presser foot base is pressed elastically onto the top side of the material to be sewn. The sewing needle with the upper thread is pierced into the material to be sewn at least approximately vertical to the plane of the material to be sewn and is pulled out again in the opposite direction. The material being sewn can be shifted, e.g., by a feeder, into the new position required for the next sewing stitch before this next sewing stitch is performed. Alternatively, the material to be sewn could also be tensioned in an embroidery hoop. Through the use of an x-y motion device, the embroidery hoop is shifted step by step, such that the next piercing position of the material being sewn comes to lie under the sewing needle. The movements of the embroidery hoop are controlled by the sewing machine controller or alternatively by a PC or by an external controller and are performed coordinated with the stitch movements of the needle bar. In the case of another alternative application, e.g., darning or quilting, the sewing material is shifted manually in the plane of the sewing material. These techniques are assumed to have been known for a long time.
It is also known to use different tools for processing the material to be sewn instead of sewing needles. Thus, for example, instead of a single sewing needle or multiple sewing needles, a cutting needle could also be attached to the needle bar, wherein this cutting needle could be used for cutting the sewing material.
From JP7133575, another alternative application of a sewing machine for the point-by-point application of inks on a piece of cloth or paper is known. The textile or non-textile, sheet material is here tensioned in an embroidery hoop or held by this hoop and can be shifted in the sewing plane underneath the needle bar by the x-y drive of this hoop. A plotter pen or ink stamp is mounted rigidly on the lower end of the presser foot bar. Driven by a hopper mechanism, the presser foot bar with the plotter pen or the stamp can be lowered onto the material to be sewn and lifted again. Just like for embroidery, the material being sewn is shifted step by step according to the print pattern to be created. Instead of the construction of sewing stitches by a sewing needle held on the needle bar, however, image points are created by lowering and raising or lifting the presser foot bar onto or from the sewing material.
One disadvantage of this method lies in that this device can be used only for specially equipped sewing machines. In addition, the stroke of the hopper mechanism is relatively small. This can lead to problems especially in the case of thick cloths or in the case of several cloth layers.